CD69 is a type II transmembrane protein that belongs to the C-type lectin family. CD69 is broadly employed as an indicator of lymphocyte activation (Non-Patent Literature 1), and thus far has been reported to be involved in inflammatory diseases such as local inflammation, arthritis, and allergic airway symptoms (Non-Patent Literatures 2 and 3).
In recent years, it has been reported that CD69 interacts with myosin regulatory light chain polypeptide (Myl)9 which is one of the subunits configuring myosin, and with this, therapeutic strategies of inflammation diseases that target Myl9 have been brought under view (Patent Literature 1).
An immune checkpoint inhibitor is a group of recently developed anti-cancer drugs and it inhibits proteins expressed in cancer cells and lymphocytes (T cells) which put the brakes on immune system. The proteins are called immune checkpoints. Programmed cell death protein-1 (PD-1), programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and the like are known to act as immune checkpoints. Several immune checkpoint inhibitors have been approved as drugs and their therapeutic uses include malignant melanoma, non-small cell lung cancer, renal cell carcinoma, malignant lymphoma, multiple myeloma, head and neck cancer, and urothelial cancer. In addition, treatment of immune checkpoint inhibitors alone or in combination with other anti-cancer drug is effective against cancers such as colorectal cancer, breast cancer, hepatocellular carcinoma, gastric cancer, esophageal cancer, ovarian cancer, small cell lung cancer, mesothelioma, endometrial cancer according to clinical trial results.